This invention is an improvement upon the rotary drill illustrated and described in U.S. Pat. No. 3,561,545. In that patent, a fluted kelly bar is provided with annular shoulders into which plungers project radially and are withdrawn by means of levers operated manually. Because the chuck in which the plungers are mounted rotates with the kelly bar, the rotation has to be stopped to permit the levers to be actuated manually, and the kelly bar released.
One of the objects of this invention is to provide, in a rotary drill of the type described in U.S. Pat. No. 3,561,545 with a kelly bar fluted and shouldered as in that patent, means actuated by a control remote from the chuck for moving the plungers.
Another object is to provide such means that can be operated while the chuck is rotating.
Other objects will become apparent to those skilled in the art in the light of the following description and accompanying drawing.